Helsinki is the capital and most populous city in Finland. It is located on the shore of the Gulf of Finland and serves as the seat of the Uusimaa region in southern Finland. Approximately 675,000 people live in the municipality, with 1.25 million in the capital region, and 1.58 million in the metropolitan area. As the most populous urban area in Finland, it is the country's most significant centre for politics, education, finance, culture, and research. Helsinki is situated 80 kilometres (50 mi) to the north of Tallinn, Estonia, 360 kilometres (220 mi) to the north of Riga, Latvia, 400 kilometres (250 mi) to the east of Stockholm, Sweden, and 300 kilometres (190 mi) to the west of Saint Petersburg, Russia. Helsinki has significant historical connections with these four cities.

A capital city or just capital is the municipality holding primary status in a country, state, province, department, or other subnational division, usually as its seat of the government. A capital is typically a city that physically encompasses the government's offices and meeting places; the status as capital is often designated by its law or constitution. In some jurisdictions, including several countries, different branches of government are in different settlements, sometimes meaning multiple official capitals. In some cases, a distinction is made between the official (constitutional) capital and the seat of government, which is in another place.